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(No Model.) 2- Sheets-Sheet 1. F. M. STEVENS.

VALVE GEAR.

No. 269,737. Patented Dec. 26, 1882.

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(No Model.) 2 Sheets-Sheet 2.

F.- M; STEVENS.

VALVE GEAR.

Patented Dec. 26

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N. PETERS Pnuwmho n mr. Washingium D104 UNITED STATES ATENT FFICE.

FRANK M. STEVENS, F CONCORD, NEYV HAMPSHIRE, ASSIGNOR TO THE STEVENS LOGOMOTIVE AND MACHINE COMPANY, OF NEW YORK, N. Y.

VALVE-G EA R.

SPECIFICATION forming part of Letters Patent No. 269,737, dated December 26, .1882.

' Application filed March 10, 1882. (No model.)

To all whom it may concern Be it known that I, FRANK M. STEVENS, a citizen of the United States, residing at Uoncord, in the county of Merrimack and State of New Hampshire, have invented certain new and uset'ul Improvements in Valve-Gears 5 and I do hereby declare that the following is a full, clear, and exact description of the same, reference being bad to the annexed drawings, makro ing a part of this specification, and to the letters and figures of reference marked thereon.

The valve-gear, as shown, represents its tip plioation to the ordinary locomotive-engine,

though it is adaptable for use upon any gas or V 1 5 steam engine. Its object is to provide a valvegear by which the steam may be used more expansively and with greater economy than has been heretofore accomplished. It consists also of several novel and useful features, hereinafter described.

Figure 1 is a plan of my improved expansion-cam, with its attachmentsfor reversing, and also themultiplying-lever, with valve-rod attachment. Fig. 2 is a longitudinal section through the center of Fig. 1. Fig. 3 is a transverse section of the cam and cam-shaft cut through at the point A, Fig. 1. Fig. 4 is a transverse section of cam and cam-shaft cut through at the point B, Fig. 1, together with 0 an elevation of the multiplying-lever D. Fig. 5.is a transverse section of cam and cam-shaft cut through at the point C, Fig. 1. Fig. 6 is a plan, showing means of transmitting rotary motion from main driving-axle of a locomotive to thecam-shaft. Fig. 7 is a side elevation of Fig. 6.

The drawings,.as given in Sheet 1, show only one side of a locomotive, the gear upon the opposite side being similar in all respects in its 0 construction and operation.

The steam-cylinder and valves may be of the pattern in ordinary use, or of any desired construction operating in a similar manner.

In the rear of the cylinder and at a suitable 5 distance therefrom, extending from side to side of the locomotive, the revolving cam-shaft E is secured in journals near each end, having cranks F outside of the journals for connecting with the main crank-pins, as hereinafter described. The cam G is fitted around the camshaft E, and is made to revolve with the shaft by means of the feather a, but is so arranged as to allow a lateral movement upon the shaft. The cam-shalt E, and cam G surroundingit, are encircled by a lever, and whichis represented by D in Figs. 1, 2, and 4. This lever is made in the form of a ring, allowing the cam to pass through its center and bear upon rolls I) b, fixed upon the interior of its opposite sides, and it is so placed that it may be operated by any point on the cam G by moving the cam laterally. The lower end of the lever Dis attached to the framework of the engine by a pivot'or hinge in such manner as to allow a reciprocating motion of its top portion when operated 6 by the cam inside it. The valve-rod H is suitably attached to the upper part of the lever D, and partakes of this reciprocating motion.

A groove or channel, 61, is out into the circumference of the extended portion of the cam G, near its inside end, into which a clutth,f, is fitted, its under side being smoothed andprepared for sliding backward and forward on the bar N. To this clutch is attached arod, 9, its other end pivoted to one end ofthe arm h, which arm is rigidly secured at its center to the shaft M. The shaft M is journaled vertically through the bar N and to it. Beneath the bar N is rigidly secured the lever J, to

be operated by any suitable connections with So the reverse-lever. Rotary motion is communicated to the cam-shaft E by means of the rods K L, Figs. 6 and 7, and their intermediate levers, 0 0, one end of said rod L being pivoted to a crank on the driving-wheel and the opposite end of the rod K being pivoted to a crank, I on the end of the cam-shaft E, similar connections being made upon the 0pposite side of the engine to the other end of the cam-shalt E. The cranks F F, upon the opposite ends of the cam-shaft E, are set at difl'erent angles, and consequently the cranks upon the driving-wheels must be set at nearly the same angles substantially as shown and described in my United States Patent, No. 246,236, dated August 23, 1881 The bearing for the cam-shaft E may be made in one piece with the base, to which the lever D is attached or separately, as desired. The cam G is of the same diameter throughout its entire length where intended to operate within the lever, the cam movement being determined by the relation of the cam G to its shaft E at the cam, by which construction I am enabled to point of bearing upon the lever I). That portion of the cam G which is directly within and opposite to the lever l), as shown in Fig. 1, has all points of its circumference equally distant from the center of the cam-shalt E, in which position it may revolve within thelever 1) without communicating motion thereto. A movement of the reverse-lever in one direction serves by its connections to draw the cam G forward upon the cam-shaft E by means of the clutch f, so that a different section of the cam is brought within the lever, and a motion corresponding to that position is communicated to the lever I) by the revolving cam-shalt. By moving the reverse lever in an opposite diretion the cam G is moved backward upon the cam-shat'tE, and the relative movement of the lever D to the movement of the piston-rod is instantly changed, and by these means I am enabled to run the locomotive in either direction. Thecross-sections ot' cam shown in Figs.

5 and 5, will indicate the relative difference of the cross section of earn shown in Fig. 4 the projection or length of the cam on its circuin t'ereuce is shorter than at other parts of the close the valve quicker and use the steam more expansively. By thus varying the length of the difi'erent portions of the cam any desired movement of the valve-rod or distribution of steam in the cylinder is obtainable.

Vhat I claim as new, and desire to secure by Letters Patent, is-

1. The rii'ig-lever D, attached to the framework of the engine by a pivot or hinge, and carrying rollers b, and the cam G, and clutch f, in combination with the bar N, arm It, shaft M, and lever J, all arranged to operate substantially as and for the purpose set forth.

2. The ring-lever I), attached to the framework of the engine by a pivot or hinge, and carrying rollers I). cam Gr, shaft E, and the clutch f, in combination with the rods K L, and their lever 0, arm h, shaft M, and lever J, all constructed and arranged as and for the purpose specified.

In testimony that I claim the above I have hereunto subscribed my name in the presence of two witnesses.

F tA-NK M. STEVFNS.

\Vitnesses HENRY ROBINSON, EDGAR II. WoomrAN. 

